The present invention relates to an arrangement for the distribution of cooling liquid in the cooling jacket of an internal combustion engine, and particularly an internal combination engine having cylinders disposed in-line or in a bank of cylinders in the engine.
The arrangement is applicable in engines in which the cylinders are disposed in-line in the cylinder block (in the case of an in-line engine) or in each bank or row of cylinders (in the case of a vee-engine). In either case, the cooling jacket includes a cooling liquid inlet chamber and a cooling liquid outlet chamber at the ends of the rows of cylinders, and the cylinder block/bank of cylinders with associated cylinder head contains mutually interconnected cooling liquid spaces and ducts which communicate with both chambers.
An internal combustion engine converts approximately only one-fourth of the heat evolved into useful work. The remaining heat has to be led away to prevent engine overheating. When the engine is running at full capacity, the surplus heat is removed by the exhaust gas system, by internal friction, by heating of lubricating oil and by the cooling system. The heat led away by the cooling system may amount to 30-35% of the heat evolved by the engine. An effective cooling system (in the present case, a liquid cooling system) is therefore absolutely necessary for an internal combustion engine to operate properly.
The heat evolved in an internal combustion engine is not evolved uniformly throughout the engine, since certain portions of the engine are particularly subjected to heat, namely the cylinder tops with the combustion chambers, exhaust gas ports and exhaust gas ducts, and the upper portions of the cylinder barrels.
The portions of a liquid cooling system which are part of the engine therefore have to be designed so as to achieve particularly effective cooling for the aforesaid portions of the engine which are most subjected to heat. To this end, a plurality of design solutions have been developed which in different ways endeavor to achieve such "specifically directed" effective cooling of certain portions of an internal combustion engine.
For instance, there is a previously known solution whereby the engine cooling water inlet and outlet are placed at the same end of the engine and a cooling water pipe is inserted in the cooling jacket in order to lead all the cooling water supplied via the cooling water inlet towards the cylinder situated furthest from the inlet, thereby making all the cooling water pass all the cylinders before it reaches the cooling water outlet.
DE A13 810 852 describes a diesel engine which is convertible from oil cooling to water cooling owing to the cylinder head being so designed as to be usable both for oil cooling and for water cooling. To make this possible, there is in the cylinder head a distribution pipe which runs in the longitudinal direction of the cylinder head, serves only as a cooling water line and receives cooling water from the cooling jackets of the cylinders via a plurality of holes in the cylinder head.
EP A10 088 157 describes a cylinder head which is intended for a water-cooled internal combustion engine and in which there are a number of separate cooling water nozzles (orifices) which feed flows of cooling water in between the valves.
U.S. Pat. No. 3,901,300 describes an internal combustion engine in which the cooling system includes separate cooling water nozzles disposed in the cylinder head to create cooling water flows directed towards desired portions of the engine, and U.S. Pat. No. 3,818,878 describes a cylinder head with a cooling liquid conveying arrangement which makes cooling liquid flow between the adjacent exhaust gas ports and around the fuel injection pipe of each cylinder before it can flow on to other portions of the cooling liquid chambers.
U.S. Pat. No. 2,845,051, U.S. Pat. No. 1,822,856, GE,A,2155545 and JP,A63-12816 also show alternatives to distribution pipes.
None of these known arrangements, however, affords a design solution which uses only one flow conveying device to achieve the desired particularly effective cooling of the portions of an engine of the type indicated in the introduction which are most subjected to heat while maintaining substantially equal cooling of each cylinder.